/Engine/Source/Runtime/Engine/Classes/Engine/World.h
Given a loaded editorUWorld, duplicate it for play in editor purposes with OwningWorld as the world with the persistent level.
static [UWorld](API\Runtime\Engine\Engine\UWorld) * DuplicateWorldForPIE ( const [FString](API\Runtime\Core\Containers\FString) & PackageName, [UWorld](API\Runtime\Engine\Engine\UWorld) * OwningWorld )